Manufacture of electrodes for secondary batteries or storage-cells.



'nnrrnn snares rarnn'r VICTOR DE KARAVGDINE, 0F BILLANCOURT, FRANCE, ASSI GNOR OF ONE-HALF TO SERGE IBERDITSCHE'WSKY APOSTOLOFF,

OF LONDON, ENGLAND.

MANUFACTURE OF ELECTRODES FOR SECONDARY BATTERIES 0R STOEtAGE-CELKS.

memes.

Ito Drawing. Application filed october Specifieatlon of Letters Patent.

Patented @ct. 3, 19121,

5,1910. Serial No. 585,39.

To all whom 'it may concern:

Be it known that I, Vroron on KARA- rooms, a subject of the Emperior of Russia, and resident of 11 Rue Theodore, Billancourt, Seine, France, have invented certain new and useful Improvements in the Mannfacture ofElectrodes for Secondary Batteries or Storage-Cells, of which the following is a specification.

This invention has for its objectthe pro duction of plates or electrodes for secondary batteries or storage cells possessing to a marked extent the valuable qualities pf large capacity per unit weight, combined with coherence of the active material and mechanical strength.

I have discovered a process by which the difficulty hitherto experienced in making use of lead sulfate for the production of such plates or electrodes may be overcome and whereby it is consequently made possible to employ lead sulfate alone as the source of the active material. The process of this invention is as follows. The lead sulfate is brought to a thick pasty condition by the addition of ammoniacal liquor or solution, and before the paste dries is molded to the required shape; or the lead sulfate may be broughtto a thick pasty condition with water, molded to shape and, before it is quite dry, exposed to the action of gaseous ammonia, or is immersed in a concentrated ammonia bath for about a quarter of an hour. The action of the ammonia results in the paste setting into a hard mass when dry.

It will be understoodt-hat the order of treatment of lead sulfatewith water and ammonia is immaterial; the sulfate may be made into a paste with an ammoniacal solution, it may be made into a paste with water and subsequently exposed to ammonia gas or it may be made into a paste with water and subsequently ii'nmerscd in a concentrated ammonia bath. In each case the process is a treatment with water and ammonia. The three methods are equivalent and are intended to be included by the phrase, treating lead sulfate with water and ammonia, in the claims. The plates or masses of lead sulfate are thereafter immersed ina formation bath constituted by a saturated solution of ammonium sulfate and a suflicient quantity of ammonia {say approximately 5%) to keep the bath in an alkaline condition, in which bath the lead sulfate is reduced spongy lead in the usual manner with dummy plates by the passage of an electric current. During this operation care must be taken to preserve the bath in an alkaline condition by the addition, from time to time, of further quantities of ammonia. Such of the formed plates as are required for positive plates may be converted' into peroxid plates in the usual manner. With a view of still further increasing the porosity of the mass, I may add to the lead sulfate, before it is made into a paste, a certain quantity of ammonium sulfate, the proportion in the case of the. positive plates being 1 to 10% by weight, and in the case of the negativeplates 5 to 30% by weight. The plastic material prior to hardening may be applied to a grid or other conductive support; or in lieu of employing a support of the usual type I may embed a conducting wire or skeleton in the mass before it has hardened. Moreover, since the masses of active material obtained by this process are coherent and self-supporting, the plates or electrodes may, if desired, be unprovided with any mechanical support.

Claims 1. The process of making electrodes for secondary batteries which consists in treating lead sulfate with water and ammonia, and subjecting the product thus formed to electrolytic treatment in an alkaline bath.

2. The process of making electrodes for secondary batteries which consists in treating lead sulfate with water and ammonia,

molding this mixture to the required shape.

and subjecting it to the action of an electric current in an alkaline bath.

3. The process of making electrodes for secondary batteries which consists in treating lead sulfate with water and mmonia, molding the paste thus formerhi 1 the required shape and subjecting it to electrolytic treatment in an alkaline bath of ammonium sulfate and ammonia.

4.. The process of making electrodes for secondary cells consisting in making a of lead sulfate, water and ammonia, form ing this paste to the desired shape and convertinq it to spongy lead by electrolysis in a solution of ammonium sulfate maintained alkaline by ammonia.

5. The process of making electrodes for secondary cells which consists in treating lead sulfate with water and ammonia, subjecting the product thus formed to electrolytic treatment in an alkaline electrolyte to form spongy lead and electrolytically treat- 10 ing this spongy lead to form lead peroxid.

JAMES HENRY BOYD, CARL R. L001. 

